Here is a photo of standard and magazine with straightened tab.][URL=http://s1356.photobucket.com/user/antqrr/media/2310_zpsmtyf9hwl.jpg.html][/url]

Here is a photo comparing the R51 magazine i altered VS S&W Shield, S&W M&P Compact, and CZ75.
Also, I compared feed length of 5 different 9mm including Glock.  All have approximately the same length feed rails.
All I can say is this worked well for me and the altered magazine is not much different from other makes.  None have the bent inward tab.

][URL=http://s1356.photobucket.com/user/antqrr/media/IMG_2311_zps9b3wyfuk.jpg.html]][/url]

Here is another photo from the top comparing the original R51 magazine,modified R51 magazine, to my S&W M&P magazine.

[URL=http://s1356.photobucket.com/user/antqrr/media/IMG_2317-2_zpsmai2wrtu.jpg.html]] to my S&W M&P magazine.

Quote from: paul7177 on January 23, 2017, 09:03:16 AM
Here is another photo from the top comparing the original R51 magazine,modified R51 magazine, to my S&W M&P magazine.

[URL=http://s1356.photobucket.com/user/antqrr/media/IMG_2317-2_zpsmai2wrtu.jpg.html]] to my S&W M&P magazine.

paul,
     Glad you got the hang of posting photos.  Way above my pay grade.  Good pics.
Blackie

Well, it appears that your mags are the same as mine. No idea why I and others have no jams, and you do. I would suggest possibly limp wristing the gun (which could cause a nose down effect on the rounds), But people get touchy when others suggest possible operator error. 

Quote from: Texas-Mark on January 23, 2017, 12:16:02 PM
Well, it appears that your mags are the same as mine. No idea why I and others have no jams, and you do. I would suggest possibly limp wristing the gun (which could cause a nose down effect on the rounds), But people get touchy when others suggest possible operator error. 

I thought of that, but have made sure I am not doing that. Just that it shot like a well oiled machine after I modified the magazine. It isn't that it did not work frequently with the original magazine, but had too many failures to feed with hollow points. I used ammunition from several manufacturers, no cheap ammo. Hollow points were my main concern and I could not trust the gun.  The modified magazine is very close to my S&W M&P magazines in shape. When I conversed with the Remington technical person, he thought it was fine.
I have no other explanation, but I just do not like the inward bend at the front and in my mind it is not needed.
BTW, there are many others that have seen similar issues. So the answer is?

Great write-up and photos.  Thank you.

Just got my new R51 Friday.
So far only 84 rounds of Winchester Forged, steel case, round nosed ammo
First off, I saw the bent up and back lip and commented to myself, "No Way Jose"!

And sure enough, some of those RNs hung up on it!
I actually thought about straightening them but wanted to look here first.

So, now to run a number of other brands, shapes and types through them, but I would hazard a guess that they will become "straight" not very far into the future.

Quote from: paul7177 on January 20, 2017, 01:16:25 PM
After many instances of having a round nosedive, especially hollow points, in my magazines, usually the 2nd round, I feel I have solved my problem. My solution was to bend the inward tab at the front of the magazine straight and polish the inside of the tab. Yesterday I put well over two hundred rounds of 4 different brand hollow points thru my R51 without a single malfunction! I also shot about 50 rounds of ball ammunition without a failure.
I have gone from an unhappy R51 owner to a happy one!

Paul,
  I am getting ready to try my number #5 mag tomorrow with the inward tab bent straight.
I'll let you know!
Blackie